Acute Nickel Toxicity Responses of Labeo rohita and Cirrhinus mrigala

Saima Naz1*, Ahmad Manan Mustafa Chatha2, Saba Saeed1

1Department of Zoology, The Government Sadiq College Women University, Bahawalpur-63100, Pakistan.

2Department of Entomology, Faculty of Agriculture and Environment, The Islamia University of Bahawalpur-63100, Pakistan.

Abstract | The exposure of acute nickel toxicity (96-hr LC50 and lethal concentrations) for two fish species viz. Labeo rohita and Cirrhinus mrigala was determined in this study. During metal stress trials both species were kept at constant temperature (32°C), pH (7) and hardness (250 mg L-1) of water. Physico-chemical parameters of test medium were monitored regularly. The observed mean LC50 and lethal concentrations for Cirrhinus mrigala were 55.85 ± 2.84 and 128.44 ± 9.25 mg L-1, respectively. On the other hand, for Labeo rohita, mean values of LC50 and lethal concentrations were calculated as 56.42 ± 2.51 and 120.98 ± 7.18 mg L-1, respectively. Cirrhinus mrigala had lower LC50 but higher lethal dose. Two fish were different in size as well. A significant positive correlation of metallic ion concentrations was observed with sodium, potassium, carbon dioxide and electrical conductivity whereas an inverse relationship was obtained with dissolved O2 for both Labeo rohita and Cirrhinus mrigala test mediums. It is concluded that acute concentration of nickel is lethal for both fish species with a significant difference of LC50 and lethal concentrations among two fish species.

Novelty Statement | The study is novel in recommending continuous monitoring of metal contamination in fish species to ensure the sustainability of this food for human consumption.

Article History

Received: April 16, 2021

Revised: May 03, 2021

Accepted: May 18, 2021

Published: June 13, 2021

Authors’ Contributions

SN conducted the research work. AMMC helped in statistical analysis. SS provided assistance during the manuscript write-up.

Keywords

Fish, Acute exposure, Lethal, 96-hr LC50, Heavy metals

Corresponding Author: Dr. Saima Naz

[email protected]

To cite this article: Naz, S., Chatha, A.M.M. and Saeed, S., 2021. Acute nickel toxicity responses of Labeo rohita and Cirrhinus mrigala. Punjab Univ. J. Zool., 36(1): 63-69. https://dx.doi.org/10.17582/journal.pujz/2021.36.1.63.69

Introduction

Pakistan is an agricultural country that relies on the water assets such as rivers, ponds, lakes and streams. The water quality is continuously falling apart due to untreated industrial waste and freshwater becomes more contaminated (Kousar et al., 2020). It causes harmful effects not only for fishes but also shows adverse consequences on other planktonic water bodies due to the presence of heavy metals such as Zn2+, Cd2+, Mn2+, Ni2+ and Pb2+ (Javed and Mahmood, 2001). Aquatic environment becomes affected due to different heavy metal sources for example industrial waste, petroleum, acid rains and metal ions leaching process of soil (Olsvik et al., 2000). The higher concentration of heavy metals creates a major issue for aquatic system and we are pushed back to a contaminated world (Asaolu, 2002). Heavy metals do not show any bending in water and inhabit the sediment quickly because of their specific properties of having more thickness as compared to water (Ghosh et al., 2018). This type of contaminated water with surplus amount of heavy metals causes an increase in the permissible limits of water (Chiu et al., 2011).

Penetration of heavy metals occurs through different ways such as gills, skin (ion exchange), ingestion and tissue adsorption process (Ahmed et al., 2014). Many factors affect the metal accumulation in various body parts such as solubility of water, mode of feeding and ecology. Another most important factor includes the physiology of fish as like age, specie, size, bioavailability, body health, reproductive circumstances and varying habitats (Foveau and Dauvin, 2017; Perugini et al., 2014).

Although due to presence of various pollutants, consumption of fish may become a threat for human beings. These chemically metallic substances are highly dangerous even at very low concentrations. Heavy metals are essential components of earth crust that occurs naturally and also measured as natural elements of aquatic system with limited permissible concentration. Now due to intense agricultural and industrial activities, its level of concentration has been increased (Zhang et al., 2011; Martín et al., 2015; Munari et al., 2017).

Specific toxicity tests are performed to check out harmful effects of heavy metals on aquatic creature (Akter et al., 2008; Javed, 2013). It allows to establish a dose-response relationship to find adverse effects of contaminants on the aquatic fauna and discharge rate of pollutants in aquatic organisms (Association et al., 1915). Acute toxicity tests are performed to determine the impact of pollutants on aquatic systems during their life expectancy (Ebrahimpour et al., 2010; Javed, 2012), to analyze metal toxicity on fish biology (Javed and Saeed, 2010), to monitor their ability of adaptation under toxic levels and to estimate various possible toxicity impacts on them (Abdul et al., 2009; Azmat et al., 2012). Low level of essential metals i.e. copper, nickel, zinc, chromium, iron and cobalt causes various infections while their high level may also cause toxicity (Sivaperumal et al., 2007; Abadi et al., 2015). Low concentration of nickel is less damaging when present in fresh water bodies and it may be causes any type of morphological change or any chromosomal aberration within cells (Magyarosy et al., 2002).

Now, fresh water bodies contaminated with pesticides have become a major issue that effect aquatic organisms badly (Indirabai et al., 2010; Iqbal et al., 2012; Naz and Javed, 2012). Heavy metals toxicity in rivers have shown adverse effects on native fish fauna including carps such as Catla catla, Cirrhinus mrigala and Labeo rohita. (Rauf et al., 2009; Azmat et al., 2012). Although among all pollutants, metals are of vital concern due to their diverse impacts as it causes toxicity in fish (Abdul et al., 2009). Keeping in view of toxic effects of nickel on aquatic habitats, posing threats to the freshwater fish, the present investigation was conducted to study the response of Labeo rohita and Cirrhinus mrigala to acute (LC50 and lethal) toxicity of nickel.

Materials and Methods

The current work was performed in Zoology Laboratory, The Govt. Sadiq College Women University Bahawalpur. To evaluate the acute toxicity effect of nickel on Labeo rohita and Cirrhinus mrigala, a 96-hr LC50 and lethal concentrations trials were carried out at 7 pH, 32°C temperature and 250 mg L-1 hardness of water in 70 liters glass aquaria. Fish were allowed to adapt the laboratory conditions for 12 hours prior to start of the experiment. A desired amount of pure compound NiCl2 was mixed with de-ionized water. Then required metal dilutions was prepared from the stock solution. Different fish used for 96-hr LC50 as well as for lethal toxicity tests were mentioned below (Table 1).

 

Table 1: Average fish weight and total length used for acute toxicity experiments.

Fish age (Days)	Fish species	Wet weight (g ± SD)	Total length (mm ± SD)
84-day	Cirrhinus mrigala	2.12 ± 0.11	55.88 ± 0.36
	Labeo rohita	1.64 ± 0.11	51.21 ± 0.09

 

For each test concentration, 20 fish of each species were kept in each glass aquarium for a period of 96-h. To prevent the fish from stress, metal concentration of each aquarium was gradually increased, 50% test concentration maintained in 3.5 hours along with full toxicant concentration in 7 hours. All test mediums were provided with constant air through air pump installed in each aquarium. Metal concentration for each fish species varied from zero with an addition of 0.05 and 5 mg L-1 (as a total concentration) for lower and higher concentrations. Fish mortality and physico-chemical variables (temperature, pH, total hardness, dissolved oxygen, total ammonia, sodium, potassium and carbon-dioxide) were recorded at 12 hours interval during 96 hours for each experimental trial (APHA, 1998). The experiment was ended after completion of 96-h of experiment. There were three replications for each experiment. The number of dead fish were counted during the experiment.

Statistical analysis

The complete data obtained after experiment was then statistically analyzed using micro-computer according to Steel et al. (1996). To check the statistical variations among different variables, Analysis of Variance (ANOVA) and Duncan’s Multiple Range tests were carried out. In addition, correlation was also used to find associations among different factors. Probit Analysis Method (Hamilton et al., 1977) was used to analyze data on percent fish mortality that was attained during 96-h LC50 and lethal concentration experiments.

Results and Discussion

An experiment was performed for 84-day age groups of two fish species viz. Cirrhinus mrigala and Labeo rohita. Separate experimental tests were performed for their sensitivity towards nickel LC50 and lethal concentrations with 95% confidence interval. To determine their 96-hr LC50 and lethal responses, both species were exposed to variable water-borne nickel concentrations. Mortality data was analyzed through Probit analysis (Table 2). The obtained mean values of 96-hr Ni LC50 for Labeo rohita were as 56.42 ± 2.51 mg L-1 with confidence interval range of 51.45 - 61.52 mg L-1 whereas its mean lethal concentration was monitored as 120.98 ± 7.18 mg L-1 among confidence interval of 109.09 - 138.35 mg L-1. High significant results were shown by probability graph of regression coefficient which demonstrates the fillness of regression line (Figure 1). At 95 percent confidence interval, normal distribution of data showed the mean Cirrhinus mrigala LC50 value as 55.85 ± 2.84 mg L-1 among confidence interval range of 50.37 - 61.81 mg L-1 whereas the mean lethal concentration was obtained as 128.44 ± 9.25 mg L-1 with confidence intervals of 113.47 - 151.57 mg L-1 (Figure 2). Statistically different responses (i.e. p ˂ 0.05) were observed for both fish species. Significantly more sensitive response for 96-hr LC50 was shown by Cirrhinus mrigala and significant low lethal response was shown by Labeo rohita (Table 2). Complete data concerned with correlation coefficients along with physico-chemical variables and nickel exposure concentrations of test mediums meant for both fish species was mentioned in Tables 3 and 4. A significant positive correlation of metallic ion concentrations was found with CO2, sodium, potassium, electrical conductivity and total ammonia. However, an inverse relationship was obtained with dissolved O2 of test mediums, suggesting that different physio-chemical parameters may have significant impact on the obtained results of the experiment hence, their value must be kept on record throughout the experimental duration to keep avoid the unwanted impact of these parameters on actual experimental variables.

 

Table 2: Mortality rate of fish during acute nickel exposure for 96 hours.

Fish age (at the start of the trial)	Nickel exposure concentrations (mg L-1)	Fish mortality (%)
		Labeo rohita					Cirrhinus mrigala
		R1	R2	R3	Mean	R1		R2	R3	Mean
	5	0	0	0	0.00	0		0	0	0.00
	10	0	0	0	0.00	10		10	10	10.00
	15	10	10	10	10.00	10		20	20	16.67
	20	10	20	20	16.67	20		20	20	20.00
	30	20	20	20	20.00	30		30	30	30.00
84-day	40	30	30	30	30.00	30		40	40	36.67
	50	30	40	40	36.67	40		40	35	40.00
	60	40	40	40	40.00	50		50	40	46.67
	65	50	50	50	50.00	50		50	50	50.00
	70	60	60	60	60.00	60		60	60	60.00
	75	70	70	70	70.00	80		70	70	73.33
	80	80	80	80	80.00	90		80	90	86.67
	90	90	90	90	90.00	100		100	100	100.00
	100	100	100	100	100.00	-		-	-	-
Factor	Mean Nickel Concentration (mg L-1 ± SD)
	Labeo rohita					Cirrhinus mrigala
LC50	56.42 ± 2.51a					55.85 ± 2.84b
Lethal concentration	120.98 ± 7.18b					128.44 ± 9.25a

 

ǂ:The means with different letters (a & b) in a single row are statistically different at p < 0.05.

 

Among different fish species, the acute toxicity (lethal concentration and 96-h LC50) of metals may be varying. A fish may be highly sensitive to a specific metal but at the same time that fish may show high resistant to another metal (Biuki et al., 2010). Due to variable physico-chemical features of metals, the toxicity level of different metals may fluctuate significantly (Azmat et al., 2012). Metals can penetrate into the body through different ways e.g. gills, orally intake of water, foodstuff, non-food particles and skin. Basically, metals are absorbed and transported through blood to any storage organ such as liver for metals transformation or for bioaccumulation in different fish organs (Nussey, 2000; Rauf et al., 2009). Fish skin comes in direct contact with metal ions and usually consumed with muscles so it has more chances of metal contamination (Yousafzai and Shakoori, 2006). Variations in the rate of metals accumulation among different species are species specific (Giguère et al., 2004). An exposure to waterborne heavy metals causes an observable hypersensitivity in fish (Javed, 2012).

 

Table 3: Correlation coefficients among various parameters of mediums used for Labeo rohita for nickel toxicity tests.

	Conc.	Temp	pH	T.H.	T.NH3.	DO	CO2	E.C.	Na	K	Ca
Temp.	0.276
pH	0.261	0.138
T.H.	0.250	-0.169	0.274
T.NH3.	0.830	0.205	0.231	-0.198
D.O	-0.749	-0.146	-0.179	0.175	-0.986
CO2	0.963	0.254	0.261	-.215	0.942	-0.893
EC	0.948	0.311	0.161	-0.234	0.844	-0.799	0.953
Na	0.954	0.256	0.238	-0.240	0.952	-0.907	0.998	0.952
K	0.954	0.367	0.260	-0.236	0.895	-0.846	0.972	0.981	0.970
Ca	0.473	0.524	-0.282	-0.310	0.378	-0.342	0.470	0.550	0.470	0.537
Mg	-0.067	-0.759	-0.197	-0.793	-0.096	0.094	-0.087	-0.131	-0.085	-0.204	-0.374

 

(Critical Value (2 tail 0.05) ± .531; Conc.= Concentration (mg L-1); Temp= Temperature (OC); pH; T.H.= Total hardness (mg L-1); T.NH3=Total ammonia (mg L-1); D.O= Dissolved oxygen (mg L-1); CO2=Carbon Dioxide; E.C.= Electrical Conductivity (mS cm-1); Na= Sodium (mg L-1); K= Potassium (mg L-1); Ca= Calcium (mg L-1); Mg= Magnesium (mg L-1).

 

Table 4: Correlation coefficients among various parameters of the test mediums used for Cirrhinus mrigala nickel toxicity tests.

	Conc.	Temp	pH	T.H.	T.NH3.	DO	CO2	E.C.	Na	K	Ca
Temp.	-0.146
pH	0.358	0.465
T.H.	-0.163	0.211	0.104
T.NH3.	0.841	-0.154	0.281	-0.169
D.O	-0.859	0.146	-0.253	0.129	-0.986
CO2	0.967	-0171	0.309	-0.169	0.950	-0.959
EC	0.906	-0.448	0.161	-0.290	0.795	-0.786	0.894
Na	0.931	-0.176	0.316	-0.137	0.928	-0.943	0.971	0.879
K	0.943	-0.213	0.310	-0.116	0.880	-0.911	0.958	0.868	0.983
Ca	0.242	-0.223	-0.214	0.226	0.281	-0.338	0.289	0.232	0.418	0.424
Mg	-0.249	0.258	0.236	-0.140	-0.297	0.342	-0.299	-0.267	-0.421	-0.423	0.989

 

(Critical Value (2 tail 0.05) ± .512. Conc.= Concentration (mg L-1); Temp= Temperature (OC); pH; T.H.= Total hardness (mg L-1); T.NH3=Total ammonia (mg L-1); D.O= Dissolved oxygen (mg L-1); CO2= Carbon Dioxide; E.C.= Electrical Conductivity (mS cm-1); Na= Sodium (mg L-1); K= Potassium (mg L-1); Ca= Calcium (mg L-1); Mg= Magnesium (mg L-1).

 

Current study indicated that 96-hr LC50 nickel concentration varied significantly among the two fish species as Labeo rohita and Cirrhinus mrigala. Cirrhinus mrigala has lower 96-hr LC50 (55.85 ± 2.84 mg L-1) than Labeo rohita (56.42 ± 2.51 mg L-1). On the other hand, Labeo rohita was considerably more sensitive for lethal concentrations of nickel (120.98 ± 7.18 mg L-1) than Cirrhina mrigala (128.44 ± 9.25 mg L-1). Kousar et al. (2020) examined three fish species viz. Catla catla, Labeo rohita and Cirrhinus mrigala which were exposed to chronic sub-lethal levels of nickel concentration of 70.40, 71.99 and 79.9 mg L-1 under the duration of 60 days of growth trial. The impact of nickel stress at 10, 20, 30 and 40 mgL-1 concentrations on Channa punctatus was observed for 30 days of trial (Desai et al., 2002). Kousar and Javed (2014) also determined the acute toxicity and bioaccumulation patterns of heavy metals (As, Ni and Zn) in Labeo rohita, Cirrhinus mrigala, Ctenopharyngodon idella and Catla catla. The order of metal accumulation was Zn ˃ Ni ˃ As. Compared with other fish species, Cirrhinus mrigala had significant ability towards Ni and Zn accumulation as 146.8 ± 149.1 µg g-1 and 243.0 ± 190.5 µg g-1, respectively. (Naz and Javed, 2012) described the acute toxicity of metal mixtures (Fe, Zn, Pb, Ni and Mn) in Catla catla, Labeo rohita and Cirrhinus mrigala and observed high toxicity to fish in terms of 96 hr LC50. According to Yousafzai et al. (2010), the order of metal accumulation in L. dyocheilus muscles was Zn ˃ Cr ˃ Cu ˃ Pb ˃ Ni ˃ Cd. During present study, significant differences were observed between LC50 and lethal concentrations of nickel for Labeo rohita and Cirrhinus mrigala. Mean nickel concentration LC50 for Labeo rohita and Cirrhinus mrigala was 56.42 ± 2.51 mg L-1 and 55.85 ± 2.84 mg L-1, respectively. On the other hand, the calculated mean of lethal concentration of nickel was 120.98 ± 7.18 mg L-1 and 128.44 ± 9.25 mg L-1 for Labeo rohita and Cirrhinus mrigala, respectively. Results showed that Cirrhinus mrigala has lower LC50 but higher lethal dose compared with Labeo rohita.

 

 

The correlation of physio-chemical parameters to the metal toxicity and its bioaccumulation is well documented. In our study, except for dissolved oxygen, all studied parameters like CO­2, sodium, potassium, electrical conductivity and total ammonia were directly proportional to the metal toxicity. Similar results were reported earlier stating that these physico-chemical parameters causes increase in metal toxicity for fish (Azmat et al., 2016). Yaqub and Javed (2012) also concluded that physio-chemical parameters of fish aquaria have significant effect on heavy metal toxicity studied in these media. Physico-chemical parameters such as, calcium, sodium, dissolved organic matter, and pH are reported to impact metal toxicity of different heavy metals to numerous aquatic organisms, like fish (Niyogi and Wood, 2004). Size and age of fish species also have significant effect on metal accumulation and variations shown in the results.

Conclusions and Recommendations

The current study concluded that nickel is a toxic metal for both the studied fish species when these are exposed to acute concentration of the metal in water bodies. While the LC50 of Labeo rohita is higher than Cirrhinus mrigala, the lethal concentration of nickel for Cirrhinus mrigala is slightly higher as compared to the Labeo rohita. This study further concluded that physico-chemical parameters have significant impact on acute toxicity of the metal. Hence, it is important to observe these values during experiment on nickel toxicity to obtain more valid results.

Acknowledgements

The authors are thankful to Zoology Department, The Govt. Sadiq College women University, Bahawalpur, for providing a laboratory to complete the present study.

Conflict of interests

The authors have declared no conflict of interest.

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